This patent relates to packaging for large products such as furniture and household appliances. More particularly, this patent relates to a tubular-type package support post reinforced with separate tubular structures to provide increased resistance to axial and lateral compression forces.
Warehousing and distribution environments drive the need for devices that protect products (such as furniture and appliances) from both axial (vertical) and lateral (horizontal) forces. Axial forces mainly are caused by stacking packaged products in warehouses. Lateral forces can be caused by stacking, clamp handling and basiloid handling, and also by collisions inherent in warehouse and distribution systems.
Corner posts consisting essentially of formed hollow paperboard tubes are often used to support and cushion large boxed or packaged articles during warehousing and shipping. Conventional corner posts are made of paperboard covered on one side with adhesive, wound onto a mandrel having a substantially circular cross-section, and then—before the adhesive sets—formed on a forming tool into a desired shape, typically one having a modified “L” shaped cross section. The dried finished corner posts are inserted into the corners of a package between the package and the article.
The use of corner posts placed vertically inside a package between the package and the product increases resistance to axial forces and allows packaged products to be stacked. However, as warehouse-stacking heights have increased, the likelihood that the corner posts will buckle under the increased axial compression forces, thereby allowing the package to crush, has also increased. Thus there is a need for a corner post having greater resistance to axial compression forces.
The use of corner posts also increases resistance to lateral (side) impact forces and forces caused by clamp handling and basiloid handling. It is not uncommon to use a clamp truck to move packaged appliances in a block three units high, three units across and two units deep. Such clamp handling can impart lateral forces on the packaged products of up to 2,500 PSI. Existing corner posts do not always provide sufficient protection against such large lateral forces. Thus there is a need for a corner post having greater resistance to lateral compression forces.
Various means have been considered for increasing the resistance of wound paperboard corner posts to axial and lateral forces, including increasing the thickness of each paperboard ply, increasing the number of plies, and increasing the ply strength. However, these proposed solutions can increase costs, slow down production, and make it more difficult to form posts into the desired shapes. Also, these solutions do not always result in a corner post having the desired resistance to axial compression or lateral forces due to the innate tendency of corner posts to buckle because of the high ratio of length to cross-section diameter and the relatively large span of long, flat vertical areas in the structure.
Thus it is an object of the present invention to provide a corner post having increased resistance to axial compression and lateral forces.
Another object of the present invention is to provide corner posts having different performance characteristics but the same outer post design.
Yet another object is to provide a compression resistant corner post that is less costly and easier to make than corner posts having more or thicker plies.
Further objects will appear from the description, accompanying drawings, and appended claims.